Dr. Sally Ride, an American physicist and former NASA astronaut, has died of pancreatic cancer. She joined NASA in 1978, and in 1983 became the first American woman to travel into space. From a statement on her website:

Sally Ride died peacefully on July 23rd, 2012 after a courageous 17-month battle with pancreatic cancer. Sally lived her life to the fullest, with boundless energy, curiosity, intelligence, passion, joy, and love. Her integrity was absolute; her spirit was immeasurable; her approach to life was fearless.

Sally was a physicist, the first American woman to fly in space, a science writer, and the president and CEO of Sally Ride Science. She had the rare ability to understand the essence of things and to inspire those around her to join her pursuits.